A thermal degradation mechanism of polyvinyl alcohol/silica nanocomposites

Peng, Zheng; Kong, Lingxue

doi:10.1016/j.polymdegradstab.2007.02.012

Cited by 324 publications

(198 citation statements)

References 31 publications

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“…This technique indicated a weight loss up to a temperature of 150°C which was linked to the presence of water in the PVOH polymer as KF titration confirmed that the water content of the samples ranged from 1.0 to 3.7%. The onset of thermal polymer degradation was detected at 240°C, indicating that PVOH polymers are stable under the process conditions used in the study (a maximum extrusion temperature of 180°C was used) (Alexy et al, 2004;Peng and Kong, 2007).…”

Section: Partially Hydrolyzed Pvohmentioning

confidence: 96%

Hot-melt extrusion of polyvinyl alcohol for oral immediate release applications

Jaeghere

Beer

Bocxlaer

et al. 2015

International Journal of Pharmaceutics

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The primary purpose of this study was to process partially hydrolyzed PVOH grades (degree of hydroxylation (DH): 33-88%) via HME and to evaluate them as carrier for oral immediate release dosage forms in order to improve the release rate of poorly water soluble drugs (i.e.HCT and CEL) via the formulation of solid dispersions. PVOH grades (DH > 70%) were able to solubilize HCT and CEL up to 15%, but required higher extrusion temperature, due to the crystalline nature of PVOH. The highest drug release rate was observed from hot-melt extruded PVOH samples with a high DH. While drug release from extrudates consisting of PVOH with a low DH was affected by ionic strength, there was no influence of pH and ionic strength on HCT release from PVOH samples with a higher DH. However, PVOH (DH > 70%) required higher extrusion temperatures, which could hamper its application for thermosensitive drugs. Therefore, the secondary purpose was to investigate the effect of sorbitol, a water-soluble plasticizer, on the thermal properties of hot-melt extruded PVOH (DH > 70%). The melting of PVOH/sorbitol mixture was required to establish molecular interactions between PVOH and sorbitol. These molecular interactions were reflected in the HME behavior: whereas an extrusion temperature of 180°C was necessary to process physical mixtures of PVOH (DH > 70%) and sorbitol, only 140°C was necessary during reextrusion (after quench cooling and cryomilling) of the PVOH/sorbitol mixture. In addition, the in vitro and in vivo dug release of plasticized PVOH was examined; whereas the CEL/PVOH/sorbitol system was able to maintain supersaturation during in vitro dissolution (0.1 N HCl) compared to Celebrex ® , the in vivo pharmacokinetic parameters (AUC 0-24h , C max and T max ) were highly comparable.

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Section: Partially Hydrolyzed Pvohmentioning

confidence: 96%

Hot-melt extrusion of polyvinyl alcohol for oral immediate release applications

Jaeghere

Beer

Bocxlaer

et al. 2015

International Journal of Pharmaceutics

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“…Upon irradiation of the thermally treated foils, the absorbance gradually increased ( [24]. In the dissociation products 15.1% benzenoid derivatives were determined by pyrolysis-GC-MS method.…”

Section: Spectral Changesmentioning

confidence: 99%

Investigation of a TiO 2 photocatalyst immobilized with poly(vinyl alcohol)

et al. 2017

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Immobilization of TiO2 photocatalyst was realized with application of poly(vinyl alcohol) (PVA). However, these PVA-based foils were too instable to be used for photocatalytic water cleaning. Their stability could be significantly enhanced by a thermal treatment, but this procedure generated various water-soluble derivatives such as aldehydes, ketones, and aromatic species. Photocatalytic pre-treatment of the foils proved to be suitable to remove these products from the surface of the composite. After three subsequent pre-treating cycles of irradiation and rinsing, the PVA-TiO2 foil became applicable for photocatalytic degradation of Triton X-100, a widely used non-ionic detergent. The composite catalyst kept its stability and efficiency even after some cycles of re-usage, while its surface underwent a perceptible, although quantitatively negligible degradation.

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“…The first weight loss takes place at 50-176°C due to the loss of adsorbed moisture via evaporation of the trapped water; the second stage at 200-400°C involves the elimination reactions of H 2 O and residual acetate groups because of partially hydrolyzed COL and PVA. The degradation step at 400-550°C is more complex and includes the further degradation of these polymer residues to yield the carbon dioxide and hydrocarbons (Peng and Kong 2007). In CH-PVA/HA nano composites, the surface of HA nanoparticles will contact with the CH and PVA molecules to make a coordination bond between Ca 2?…”

Section: Thermal Behavior and Experimental Design Optimizationmentioning

confidence: 99%

“…In CH-PVA/HA nano composites, the surface of HA nanoparticles will contact with the CH and PVA molecules to make a coordination bond between Ca 2? and RCOO -in CH molecules and a strong interact between the hydroxyl groups on the surface of HA and PVA hydrophilic molecules (Chang and Tanaka 2002a, b;Ficai et al 2009;Kim et al 2008;Peng and Kong 2007). These reactions were influenced on tertiary weight loss stage of CH-PVA blend materials.…”

Section: Thermal Behavior and Experimental Design Optimizationmentioning

confidence: 99%

Synthesis and character investigation of new collagen Hydrolysate/polyvinyl alcohol/hydroxyapatite Polymer-Nano-Porous Membranes: I. Experimental design optimization in thermal and structural properties

Imanieh¹,

Aghahosseini²

2013

Syst Synth Biol

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Development of bioorganic-inorganic composites has drawn eyes to extensive attention in biomedical fields and tissue engineering. So many attempts to prepare hydroxyapatite (HA), in conjunction with various binders including polyvinyl alcohol (PVA), and collagen has performed for late 20 years. We applied a method based on the phase separation for making of polymer porous membranes. This procedure is induced through the addition of a small quantity of water (polymer-rich phase) to a solution with HA precursors (polymer-poor phase). Thermal and structural composite properties of collagen Hydrolysate (CH)-PVA/HA Polymer-Nano-Porous Membranes were analyzed by Design of experiment that was undertaken using D-optimal approach, to select the optimal combination of nano composites precursor. The resulted composite characters were investigated by Fourier transform infrared, scanning electron microscopy (SEM) and thermal gravimetric analysis. Based on the SEM images, this new method could be clearly concluded to porous CH-PVA/HA hybrid materials. Finally the hemocompatibility of nanocomposite membranes were evaluated by the hemolysis study.

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A thermal degradation mechanism of polyvinyl alcohol/silica nanocomposites

Cited by 324 publications

References 31 publications

Hot-melt extrusion of polyvinyl alcohol for oral immediate release applications

Hot-melt extrusion of polyvinyl alcohol for oral immediate release applications

Investigation of a TiO 2 photocatalyst immobilized with poly(vinyl alcohol)

Synthesis and character investigation of new collagen Hydrolysate/polyvinyl alcohol/hydroxyapatite Polymer-Nano-Porous Membranes: I. Experimental design optimization in thermal and structural properties

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